This invention is related to an apparatus for the inspection of fluids. In particular, the invention is related to an improved apparatus for measuring the color of a paint flowing through the apparatus.
In the manufacture of paints, one problem is to match the color of the paint as it is being made to a standard paint color. Either a colorimeter or spectrophotometer usually is used to measure color parameters of the paint being made. Colorants such as pigment dispersions and tints are added to the paint until the color parameters match those of the standard paint color. McKinney et al. U.S. Pat. No. 3,020,795 issued Feb. 13, 1962 shows an apparatus which can be used to inspect paints. However, this apparatus is inadequate since the design of the apparatus results in a dark spot in the center of the viewing window of the apparatus caused by paint being forced under pressure up through a tapered passage and impinged on the viewing window. A colorimeter focused near the edge of the viewing window and a colorimeter focused on the center of the window will have different readings making it impossible to accurately match the paint being made to a standard paint color.
Also, there is a particular problem with paints containing metallic flake pigments. These pigments must be flowing in a parallel relationship to the viewing window and should not be tumbling in order to provide an instrument such as a colorimeter with consistent readings. There is a need for a viewing apparatus which will provide a paint stream of a uniform color without turbulent motion so that accurate instrumental readings can be taken.